Severance Payable - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2019	Mar. 31, 2020
Severance Payable [Line Items]
Salary continuance term	5 years
Reimbursement of health benefits term	3 years
Severance expense		$ 2.5
Discount rate		6.00%
Stock option modification expense		$ 0.4
Severance liability	$ 1.6		$ 1.6
Minimum [Member]
Severance Payable [Line Items]
Post-termination exercise period	3 months
Maximum [Member]
Severance Payable [Line Items]
Post-termination exercise period	5 years